Repetitive-pulse generator



March 1954 c. R. WILHELMSEN REPETITIVE-PULSE GENERATOR Filed Dec. 12, 1552 TRIGGER- PULSE GENERATOR Time IN V EN TOR.

N E S M L E H H W R L R A C ATTORNEY Patented Mar. 2, 1954 :r 25671,:1'72 .,..;aREPETITIYE-PULSEaGENERATOR 51 cm R} Will elmsen", wes' buryi N513! assignor to npl cati n bec mber 12; :1-952flSerial; No; 325,573

ment m 'appiicationswvhere the test apparatus is 'onlyrequired to have a small' du ty cycle; that is, 'tooperate di'iringa'srnall portion-"of a repetitive .cycl'e. Such test apparatus may demand a -large amounti'of pewen'du'ring' 'short 'operating' intervals 'butma'y have ar'equir'ed duty cycle of, for example only "ten? per jce'nt, of the repetitive 3 cycle.

'"Vast reductions in power consumption bythetest apparatus and ireductionsdritub sizes andthe sizes" of "other circuit components with consewent-reductions ofcost may, thereforefbe ac- '5complished-byutilizing a'pi lse typepowersupply 'whichsuppli'esjpower tothe test apparatus only (Un 25pm? erator. a f the triggered ,type f0r supp e pQWer pulses Of Q positive. polarity relative. to. a given I reference; It'is another object iof thepresent invention v provide a new "and improved v repetitive-pulse i generatorof. the tri gered type for supplyingrto ,a iow-impedance load circuit power pulses. of .-positive.-po1arity relativeto a given reference.

Y In; accordance withi a particularflform of the M m ,inventioma generatorpf the triggered type for 1 developing .r. epetiti\ re', pulses comprises a potential-supply, circuit having positive andanegative terminals and a first ,electronrdischarge device ,cc upled to. the aforesaid circuit and having an 15 input-circuit and conductive during the. intervals between repetitive-- .-.pu1ses. The generatorfalso includes a second electron discharge. device ,havingan anode; cpupledtmthe aforesaid positive :termina1,,-a eathodercoupled to the aforesaid riegativeierminaL- a. control; electrode coupled. to

, ,the above' mentioned first device, and an output e rcui inc udin a pott qni e a eiw the ewrideepew duringflthv Short r d i gintervals ,there'of. T ""fIheLpoWe pulses suppl e byaslyichiv 4 ity'pe power supplyshouid"ordinarily have""a* preforesaidyenegative terminal. and the aforesaid The; second device v is: nonconductive t ring the apove-mentioned' intervals .between ,i ,i r a a J theyrepetitive-pulses; The generator also-includes ,iyp:pdwfogfipplyt,ishbmdhbrdinarflyfibe,; =cbab1e .-to;one ofi-theiaforesaid devices for repetitively :of supplying Iarger-hmofints;,bf. pdwi thanijmse causing thefirstzdevice to be 'noncondnctive and """enrat6rs"ofmeantimetype. VarrOus' cir s fierce mm impedance edits haveheretofore-been prdposedrersuppl imeansffitcltswe -01theeaforesaldPommof F "ing""s1ich inositi newer-biases; "Such' nircnits flutpmiclrc-mt andmupled the amreswd rqfiire the g afl-Spamte gating eontrolgelectrode andvthe-aforesald cathode, tor else-generator, adding-to the ccniplexity ahd, tP ""henc e'fthe cosfofi the"powersupplv. iindrd'er to 9 aforesald t of the olttput aaavesuauwtmsetfsteam-power, The Includes; one pulse-type." ower supply circuitfhrto-fore proposed'iitilizes af pulse transifor 'ner-whichi also flddstothe complexity and the coist of the-power supply and, additionally may not oci-pantherdaily-available. It is 'an obj ect. of the; present; invention, therefore, to provide a new and improved repetitive- T lbful se generatbr bfi the i triggetd typeZltvhich evlce and to the: input i-rcuitoflthefi-rst device for: controlling the dura- .1.Ations .:'oi ;the'*: nonconductionza intervals of ithe: first Ldeviceand the conduction intervals ofthesecond a device;' wherebyathe generator is :eifectiveztoz, de-

a elopi; repetitiveprpulses-:in-ithe-t aforesaid: output of the 'above It'dsian'otherr object of 'the: present' invention l, V v I tatiprovid a-znewiamt improved repetitiveepulse .tmw t FF 9 W111 e p i mthe jugenerator. 20f:thedariggeredp' typei for suppiying fi gn f 'lc ulses ofiapredeterminedzpolarityandnne:.:wh1ch he. c m n inex n s omelatively simple: constructi n. nd d si not filize; a nul ezzt nsiorm altgisganqtherg phject. \of;.;the,presentinvention to cladding afvrepetit iv -pulse' generator of the trigeredgtype constructed,:in accordance with the weee zW etwm mn evesilnen ta.

cathode circuit Fig. 2 is a graph representing the potentialtiine characteristics of signals developed at various circuit points of the repetitive-pulse generator represented in Fig. 1.

Description of Fig. 1 equipment Referring now more particularly to Fig. 1 of the drawing, there is represented equipment including a repetitive-pulse generator of the triggered type constructed in accordance with-the invention. The equipment comprises, for example, radar test equipment including .a triggerpulse generator H) which may be of conventional construction for generating, for example, negative trigger pulses of a predetermined frequency. There is connected across the output circuit of the generator ill a cathode resistor H of a diode 12. The resistor ll and the diode K2 are coupled to a repetitive-trigger-pulse supply circuit of a repetitive-pulse generator l3 for applying negative trigger pulses thereto and for preventing the application of, for example, stray positive pulses thereto which might interfere with the operation of the generator.

The repetitive-pulse generator 13 comprises a potential-supply circuit preferably having a positive terminal +B, a first negative terminal B1, and a second less negative terminal -32. A first electron-discharge device comprising, for example, an electron tube M of the triode type, preferably has an anode I la coupled to the positive terminal +B through a series of resistors 25, 22, 26 to be described in detail subsequently, and a cathode Mb coupled to the negative terminal B1 through a cathode resistor l6 and a power-supply filter network comprising a decoupling resistor I1 and a filter condenser IS. The tube It preferably also includes a control electrode 14c coupled through a grid-leak resistor Hi to the cathode circuit thereof for developing, in a manner more fully explained hereinafter, an operating bias which maintains the tube It conductive during the intervals between repetitive pulses developed by the generator it. The repetitive-trigger-pulse supply circuit of the generator l3 comprises the control electrodejust described for repetitively causing the tube 44 to be nonconductive upon the application of trigger pulses thereto.

- The repetitive-pulse generator 13 also includes a second electron-discharge device nonconductive during the intervals between the repetitive pulses a developed by the generator 13 and comprising,

for example, an electron tube IQ of the pentode type, preferably having an anode IBu-coupled to the positive terminal +B, a cathode [9b coupled to the second negative terminal -B2 through a cathode resistor 2| and to the positive terminal +B through resistor 26, and a first control electrode I90 coupled through resistor 25 to the anode E ia oi the first electron tube [4. The tube 19 preferably also includes a second control or screen electrode led coupled to the positive terminal +B through a resistor 23 and coupled to the cathode i9b by means of a condenser 30 connected to the electrode ltd and the cathode I913. The time constant of the resistor. 23 and the condenser 30 preferably is long with respect to the duration of each output pulse ofthe generator [3 to provide a long discharge time for the condenser 30. The tube It preferably also includes a suppressor electrode lee connected to the cathode 19b in a conventional manner.

The second electron-discharge device comprising the tube 19 has, for example, ode output circuit which includes a portion prefan anode-cathmentioned portion 20,

erably coupled between the second negative terminal B2 and the cathode 9b. This portion of the output circuit effectively includes, for example, a load circuit including the cathode resistor 21 and having a predominantly resistive impedance comprising the input impedance of a power-pulse utilizing apparatus 29 which may, for example, beany apparatus utilizing repetitive power pulses for energization, such as radar test apparatus.

Impedance means exclusive of the abovementioned portion 28, 2! of the output circuit of the tube l9 and comprising, for example, the resistor 22 preferably is coupled between the first control electrode I90 and the cathode l9b of the tube 19 for applying to the control electrode i9c potential variations across the above- 2! of the output circuit of the tube 19. The previously described screenelectrode connections of the tube 19 also are such that the condenser 38 applies to the screen electrode 19d potential variations across the abovementioned portion 20, 2| of the output circuit of the tube IS.

The repetitive-pulse also includes a third generator l3 preferably electron-discharge device the triode type, having an anode 24a coupled to the positive terminal +B, a control electrode 2M2 connected to, the anode Ma of the tube hi, and a cathode 2G0 connected to the control electrode I90 of the tube l9 and coupled through a resistor 25 to the anode Ma of the tube Hi. The control electrode 241) and the cathode 240 are coupled to the tube M for maintaining the third device 24 nonconductive during the intervals between repetitive pulses.

The tube [4, the resistors 16, 25, 22, 2|, and 2t constitute a voltage divider which preferably is so proportioned as to maintain the tube I l conductive during the intervals between repetitive pulses and the tubes l9 and 2t nonconductive during those intervals.

The repetitive-pulse generator is also includes a time-constant feed-back network coupled to the output circuit of the tube It and to the input circuit of the tube M for controlling the durations of the nonconduction intervalsof the tube [4 and the conduction intervals of the tube It. The time-constant networkpreferably comprises the cathode resistor it of the tube I4 and a condenser 21 coupled thereto and to the output circuit of the tube 19 for controlling an operating bias potential of the tube l4 and, thus, the durarepetitive pulses having a Operation of Fig. 1 equipment Considering now the operation of the Fig. 1 equipment, the repetitive-pulse generator 43 is of the type which has a single stable operating mode. When the generator It operates in the stable mode, the tube It conducts, resulting in current flow from the positive terminal +B through the resistors 26, 22, 25, the tube M, and resistors-i6, IT to the negative terminal -B1. The cathode Mb of the tube 14 then is at a positive potential with respect to the terminal B1 but at a negative potential with respect to the terminal B2. Hence, control electrode-cathode current flows in 21 preferably-is-sufliciently long relative 'tothe time interval t1t2 that the exponential decrease 4' approximates a'linear decrease during that intion of the time interval tl-t2.

When the tube 14 becomes conductive, the generator 13 rapidly returns to its stable operating mode as a result of current flow through the tube 14 which renders the tubes 24 and I9 nonconductive. Because of the regenerative nature of the feedback from the cathode of the tube l9 to the cathode of the tube Hi, the changes in operating modes of the generator occur sharp- 1y with the result that the output pulse developed across the effective input impedance of the power-pulse utilizing apparatus 20 has a relatively sharp trailing edge.

The generator l3 then remains in its stable operating mode until the occurrence of th next repetitive trigger pulse supplied by the generator H] which initiates a cycle of operation similar to that just explained.

The repetitive-pulse generator 13 has the highly desirable feature that variations in loading cause compensatory variations in the driving potential applied to the control electrode-cathode circuit of the tube l9 which enable the supply circuit +B, -B2 to supply variable values of current flow through the tube I9 to meet varying load requirements. For example, if the effective input impedance of the power-pulse utilizing apparatus 20 decreases, a larger value of current flows from the terminal +B through the tube 24, the resistor 22, and the apparatus 20. The potential drop across the resistor 22, therefore,

increases, causing the potential at the control electrode I90 of the tube I9 tov rise relative to the potential at the cathode I911. Accordingly, the effective impedance of the tube 19 becomes less and the supply circuit +B, -B2 supplies higher values of current through the tube I9.

In this manner, variations in loading by the power-pulse utilizing apparatus 20 cause changes in the operating bias of the tube l9 and facilitate the supply of the required current flow by the generator l3 at an approximately constant output potential.

While applicant does not wish to be limited to any particular circuit constants, the following have been employed in a repetitive-pulse generator constructed in accordance with the invention:

Effective input impedance of power-pulse utilizing apparatus About 900 ohms.

8 Pulse potential at cathode I91) About 180 volts. Load circuit current flow during pulse About 200 milliamperes.

Time interval t1--tz .l About 220 microseconds. Over-all operating period About 4000 microseconds. Potential at terminal +B relative to potential at ter- 7 i minal Bz +315 volts.

Potential at terminal B1 relative to potential at terminal -32 volts.

From the foregoing description of the invention, it will be apparent that a repetitive-pulse generator embodying the invention has the advantage of being relatively simple in construction yet capable of supplying greater power and a higher value of current flow of predetermined polarity to a low-impedance power-pulse utilizing apparatus than could heretofore readily be provided by a repetitive-pulse generator of simple construction.

While there has been described what is at present considered to be the preferred embodiment of this invention, it will be obvious to those skilled in the art that various changes and modiiications may be made therein without departing from the invention, and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A generator of the triggered type for developing repetitive power pulses comprising: a potential-supply circuit having a positive ter-- minal, a first negative terminal, and a second less negative terminal; a first electron-discharge device having an anode-cathode circuit coupled to said positive terminal and said first negative terminal and having a control electrode-cathode input circuit including a cathode resistor and conductive during the intervals between said repetitive pulses; a second electron-discharge device having an anode coupled to said positive terminal, a cathode coupled to said second negative terminal, a first control electrode coupled to said first device, a second control electrode coupled to said positive terminal, and an output circuit which is coupled to said anode and said cathode of said second device and efiectively includes a load circuit having a predominantly resistive impedance coupled between said second negative terminal and said cathode of said second device, said second device being nonconductive during said intervals between said repetitive pulses; a circuit including said input circuit of said first device for supplying periodic trigger pulses periodically to cause said first device to be nonconductive and said second device to be conductive; a resistor connected between said first control electrode and said cathode of said second device for applying to said first control electrode thereof potential variations across said load circuit; a condenser coupled between said second control electrode and said cathode of said second device for applying'to said second control electrode thereof potential variations across said load circuit; and a time-constant feed-back network comprising said cathode resistor of said first device and a condenser coupled thereto and to said output circuit of said second device and having a time constant approximately equal to one-tenth the period of said trigger pulses-for controlling an 'operating bias potential *of-said -fii'st -'-device and thus':the 1 durations we the nonco'nduc'tion intervals oi-said firstdev'ice and-the conduction intervals"of-said'second device-whereby the generator is eifectiv'e to develop'repetitive' power pulses in sa'id output circuit. 7

2. A generator of 'the triggeredtype-fof"de- 'veloping repetitive pulses comprising: a potential-supply circuit having positive and negative terminals; 2; first electron-discharge device coupled to said circuit and "having an input circuit and conductive-during the intervals betweensaid repetitive pulses; a second electron discha rge "device having-an an'ode coupled to said positive terminal, a: cathode coupled "to said negative terminal, a zcontrol -electrodecoupled=to saidflrst device, and an output circuit includng a portion coupled :between said negative terminal and said :cathode, said second device'being nonconductive during saidintervals "between 'said repetitive :pulses; "a repetitive-trigger pulse supply circuit coupled to one of said devices for repetitively causing said "first device fto be' *nonconductive and :said second 'device to :be conductive; im-

pedancemea'ns :exclusiveof :said'portion of .said

output circuit and :coupled between said control electrode 'and:said cathode for "applying to said control :electrode potential variationsnacross said portion 1 of said output circuit; I and a "time-constanti feed-back network coupled to isaid output circuit of said second *device and to said input circuit, .iof said :first :device for controlling the durations of :the :nonconductioni intervals of said first device and the-nomination: intervals :of said second idevice; wherebyuthe generator: is effec- :tive to deve1op-:--said;:repetitive*pulses:insaid out put circuit.

3. Agjgeneratorxof the triggered type for developing. repetitive pulses comprising: a potentialsupply circuit having apositive: terminal, a first negative terminal and a second iless' negative terminal; a first electron-discharge:device :coupled to said positive terminal and said first'negativeterminal and having an input circuit and conductive during the intervals between said repetitivepulses; a second electron-discharge-devicehaving an anode coupled to said positive terminal, a 'cathodecoupled to said second negative terminal, a control electrode coupled 110 said first device, and an output circuit :including 'a portion coupled between said second negative terminal. and said cathode,:said:second device-be ing nonoonductive during" said:intervals between said repctitivepulses; a repetitive-trigger-pulse supply circuit coupledto one of said .devicesfor repetitively causing said first device :to be nonconductive and said second-device'to be conductive; impedance :means exclusive ;of :said portion of said output circuitand coupled between :said control electrodeand said cathode forapplying to said control electrode potential variationsaacross saidportion'of 'said output circuit; anda timeconstant feed-back network coupled to said output circuit of saidsecond device and to said input circuit of'saidfirst device for controlling the durations-of the nonconduction intervals of said first device and the conduction intervals of saidsecond device, whereby the generator is effective "to developsaidwrepetitive pulsesin said output circuit.

A-generator of the triggered type for developing repetitive pulses comprising: a potential supply circuith-avin-g positive and negative terminails; a first electron-discharge device coupled to said circuit and having an input-circuit and .conductive during theintervals between'saidzrepeti to be 'itive'tpulses ,2 :a csecond elecltrondischarge, device navmgranz anodemoupledr-torsaid positivettermianal, :a cathodeircoupled tozsaidi negative terminal, afirstcontroltelectrode coupled :toisaid "first :device, a second control electrode coupled to said positive terminal; andzanzoutput circuit including a :portion coupledz betweenisaid 'snegative' terminal and said cathode, .said second device being non- :cond-uctive duringzsaid intervalsbetween-said'rep'etitive pulses; a vrepetitive trigger pulsesupply circuit coupled :to one:of said devices for repetitivelyrcausing'said first deviceito be nonconductive and saidi-second-device to-be conductive; 'iimped- 'ance-ineans exclusiveof'saidportion'of said output acircuitr andvcoupledbetween: said first control electrode and said cathode for applying to :said first control electrode potential variations-iacross saidgportion of' saidroutput circuit; a-condenser coupledbetweensaid-secondcontrol electrode and said cathode forcapplying to -said. second control electrode potential wyariations across said portion of saidoutput circuit; rand a time-constantfeedback networkcoupledfto said'outputcircuit of said second' devioeand to said input :circuit :of said first device for-"controlling the durationscf the nonconduction :intervals ofsaid first device and the conduction intervals of said second -*device, whereby the generator iscffective to develop said repetitiverpulses 'inwsai-d output circuit.

5; A- -;generator of :the triggered type 'for idleveloping repetitive power rpulses comprising: a .potentialesupply cincuitzrhavingpositive andinegative terminals; a. :first electron-discharge *device coupled toesaid circuitandi havingan input circuit and conductive-during-theiintervals between said repetitive pulses; :a second electron discharge device havingan anode' coupled to said "positive terminal, .a-cathode:coupled'tosai'd negative terminal,1a control.celectrodercoupled'to said"firstde vice, and anm'output circuit which is coupled to said anode :and said cathode and 'eifectivelyincludes a load zcircuit-having a predominantly resistive impedance coupled between said "negative terminal aanda sai-d "cathode, said :second device rbeingnonconductive during "said intervals between said repetitive "pulsesy "a repetitivetrigger-pulse supplycircuitccupled to one of said devices iforrepietitively causing 'said "first device :nonconductiveand said second device to beconductive; impedance means exclusive ofisaid load oircuitecoupled betweensaid control electrode andzsaid cathode for applying ':tosaid control electrode potential ivariations across said load circuit; :and a time-constant feed-back network coupled tosaidoutput circuitof said second device and to said input. circuit-of said first device for controlling the durations of the nonconduction intervals :ofzsaid first device and theconduction intervals :of'said second device, whereby the -.:gen'erator is efiective to'tdevelop said repeti tivepower=pulses across-said load circuit.

6. -A rgenera'torof the triggered type for "developing repetitive pulses comprising: a potentialsupply circuit-having positive and negative tcrminals; a first electron discharge device coupled tovsaid 1 circuit and having 'an input circuit 1 and conductive during the :intervals between said repetitive pulses; a 'second electron discharge device having.an'anodeacoupled'to said'positivetermina'l, a102113110616IICOUDIBd tO isaid negative terminal, :acontrol; electrode coupled to said first device;:an'd:anroutput 'circuiti'includin'g a portion coupled between :said :negative' terminal and said cathode, saidrsecond "device z'being nonconductive during-r said einterva'ls ibetweenrsaid repetitive pulses; a repetitive-trigger-pulse supply circuit including said input circuit of said first device for repetitively causing said first device to be nonconductive and said second device to be conductive; impedance means exclusive of said portion of said output. circuit and coupled between said control electrode and said cathode for applying to said control electrode potential variations across said portion of said output circuit; and a time-constant feed-back network coupled to said output circuit of said second device and to said input circuit of said first device for controlling the durations of the nonconduction intervals of said first device and the conduction intervals of said second device, whereby the generator is effective to develop said repetitive pulses in said output circuit.

'7. A generator of the triggered type for developing repetitive pulses comprising: a potentialsupply circuit having positive and negative terminals; a first electron-discharge device coupled to said circuit and having an input circuit and conductive during the intervals between said repetitive pulses; a second electron-discharge device having an anode coupled to said positive terminal, a cathode coupled to said negative ter minal, a control electrode coupled to said first device, and an output circuit including a portion coupled between said negative terminal and said cathode, said second device being nonconductive during said intervals between said repetitive pulses; a repetitive-trigger-pulse supply circuit coupled to one of said devices for repetitively causing said first device to be nonconduotive and said second device to be conductive; a resistor connected between said control electrode and said cathode for applying to said control electrode potential variations across said portion of said output circuit; and a time-constant feedback network coupled to said output circuit of said second device and to said input circuit of said first device for controlling the durations of the nonconduction intervals of said first device and the cond ction intervals of said second device, whereby the generator is efiective to develop said repetitive pulses in said output circuit.

8. A generator of the tr ggered type for developing repetitive pulses comprising: a potential-supply c rcuit having positive and negative terminals; a first electron-discharge device having an anode-cathode circuit coupled to said potent al-su ply circuit and having a control electrode-cathode input circuit including a cathode resistor. said device being conductive durin the intervals between said repetitive pulses a second electron-discharge device having an anode coupled to said positive terminal, a cathode coupled to said ne ative terminal, a control electrode co-pled to said first device, and an output circuit including a portion coupled between said negative terminal and said cathode of said second device, said second device being nonconductive during said intervals between said repetitive pulses; a repetitive-trigger-pulse supply circuit coupled to one of said devices for repetitively caus ng said first device to be nonconductive and said second device to be conductive: impedance means exclusive of said portion of said output circuit and coupled between said control electrode and said cathode of said second device for applying to said control electrode thereof potent al variations across said portion of said output circuit: and a time-constant feedback network comprising said cathode resi tor of said first device and a condenser coupled thereto and to said output circuit of said second device for controlling an operating bias potential of said first device and thus the durations of the nonconduction intervals of said first device and the conduction intervals of said second device. whereby the generator is effective to develop said repetitive pulses in said output circuit.

9. A generator of the triggered type for developing repetitive pulses comprising: a potentialsupply circuit having positive and negative terminals; a first electron-discharge device coupled to said circuit and having an input circuit and conductive during the intervals between said repetitive pulses; a second electron-discharge device having an anode coupled to said positive terminal, a cathode coupled to said negative terminal, a control electrode coupled to said first device, and an output circuit including a portion coupled between said negative terminal and said cathode, said second device being nonconductive during said intervals between said repetitive pulses; a circuit coupled to one of said devices for supplying periodic trigger pulses periodically to cause said first device to be nonconductive and said second device to be conductive; impedance means exclusive of said portion of said output circuit and coupled between said control electrode and said cathode for applying to said control electrode potential variations across said portion of said output circuit; and a time-constant feedback network coupled to said output circuit of said second device and to said input circuit of said first device and having a time constant approximately equal to one-tenth the period of said trigger pulses for controlling the durations of the nonconduction intervals of said first device and the conduction intervals of said second device, whereby the generator is effective to develop in said output circuit repetitive pulses having a duration approximately equal to said time constant.

10. A generator of the triggered type for developing repetitive pulses comprising: a potential-supply circuit having positive and negative terminals; a first electron-discharge device coupled to said circuit and having a control electrode-cathode input circuit and conductive during the intervals between said repetitive pulses; a second electron-discharge device having an anode coupled to said positive terminal, a cathode coupled to said negative terminal, a control electrode coupled to said first device, and an output circuit including a portion coupled between said negative terminal and said cathode of said second device, said second device being nonconductive during said intervals between said repetitive pulses; a third electron-discharge device having an anode coupled to said positive terminal, a cathode coupled to said control electrode of said first device, and a control electrode, said control electrode and said cathode of said third device being coupled to said first device for maintaining said third device nonconductive during said intervals between said repetitive pulses; a repetitive-trigger-pulse supply circuit coupled to one of said devices for repetitively causing said first device to be nonconductive and said second and third devices to be conductive; impedance means exclusive of said portion of said output circuit and coupled between said control electrode and said cathode of said second device for applying to said control electrode thereof potential variations across said portion of said output circuit; and a time-constant feedback network coupled to said-output circuit of said second device and to said input circuit of said first device for controlling the durations of the nonconduction intervals of said first device and the conduction intervals of said second and third devices, whereby the generator is effective to develop said repetitive pulses in said output circuit.

11. A generator of the triggered type for developing repetitive pulses comprising: a potential-supply circuit having a positive terminal, a first negative terminal, and a second less negative terminal; a first electron-discharge device coupled to said circuit and having a control electrode-cathode input circuit including a first resistor coupled to said first negative terminal; a second electron-discharge device having an anode coupled to said positive terminal, a cathode coupled to said second negative terminal, a control electrode coupled to said first device, and an output circuit including a second resistor coupled between said second negative terminal and said cathode of said second device; a third resistor connected between said control electrode and said cathode of said second device for applying to said control electrode thereof potential variations across said second resistor; a third electron-discharge device having an anode coupled to said positive terminal, a cathode coupled to said control electrode of said first device, and a control electrode; a voltage divider including said first device, said three resistors, a resistor coupled between said control electrode and said cathode of said third device, a resistor network coupled between said cathode of said third device and said positive terminal and coupled to said second resistor, said voltage divider being so proportioned as to maintain said first device conductive during the intervals between said repetitive pulses and said second and third devices nonconductive during said intervals; 2. repetitive-trigger-pulse supply circuit coupled to one of said devices for repetitively causing said first device to be nonconductive and said second and third devices to be conductive; and a timeconstant feed-back network coupled to said output circuit of said second device and to said input circuit of said first device for controlling the durations of the nonconduction intervals of said first device and the conduction intervals of said second and third devices, whereby the generator is efiective to develop said repetitive pulses in said output circuit.

CARL R. WILHELMSEN.

References Cited in the file of this patent UNITED STATES PATENTS Number 

